Generally, an independent impulse noise is uniformly distributed over a frequency domain. When only a linear filter is used to remove the impulse noise, the high frequency component of the impulse noise is not effectively removed so that the details of the image are blurred.
Thus, a significant effort has been expended in various fields to deal with the impulse noise of a white nature based on the nonlinear filtering scheme described in the following literature: [1] D. H. Sargarad and J. W. Modestino, "Errors-and-Erasures Coding to Combat Impulse Noise on Digital Subscriber Loop", IEEE Transactions on Communications, vol. 38, pp. 1145-1155, Aug. 1990; [2] J. W. Lechleider, "An Adaptive Impulse Noise Canceller for Digital Subscriber Lines", Proc. of the GLOBECOM, vol. 1, pp. 36-39, December 1992, Orlando, Fla. USA; [3] G. A. Williamson, P. M. Clarkson, and W. A. Sethares, "Performance Characteristics of the Median LMS Adaptive Filter", IEEE Tr. on Signal Processing, pp. 667-680, Feb. 1993; and [4] S. R. Kim and A. Efron, "Adaptive Robust Impulse Noise Filtering," IEEE Transactions on Signal Processing, pp.